Genomic insights into the antagonistic activity of Paenibacillus brasilensis PB24 against Fusarium oxysporum: implications for biocontrol and plant growth promotion strategies

Abstract

Biotechnology and sustainable strategies are the way forward for increasing global food production. The use of plant growth-promoting bacteria to increase the productivity of important food crops helps reduce the need for land expansion, improves soil fertility and plant tolerance to adverse abiotic conditions, and increases the ability to combat phytopathogens. Paenibacillus brasilensis strain PB24 is an endospore-forming bacterium that promotes plant growth through various direct and indirect mechanisms. To improve the understanding of its ability to inhibit the fungus Fusarium oxysporum, which causes numerous agricultural pathologies, the potential of P. brasilensis PB24 as a producer of antifungal compounds was investigated. In vitro assays demonstrated fungicidal activity against F. oxysporum hyphae. Additionally, genome mining of P. brasilensis PB24 was conducted to identify biocontrol and plant growth-promoting traits. For the first time, these traits were compared with those of other Paenibacillus species, and several genetic similarities were identified. Genome mining revealed that strain PB24 produces several antimicrobial compounds, similar to fusaricidin and sevadicin, but retains substantial differences in their monomers, suggesting that they may be novel lipopeptides. A unique genetic cluster was characterized in the PB24 genome as a potential resource for the discovery of new compounds. The results demonstrate the biotechnological potential of P. brasilensis PB24 for plant growth and biocontrol of phytopathogens and provide a basis for the future development of sustainable biocontrol strategies and commercial bacterial formulations.